Heat milk, cheese, shortening, sugar, and salt over moderate heat, stirring, until cheese is melted; cool to lukewarm.
Pour warm water into a warm large bowl, sprinkle in yeast, and stir to dissolve.
Add cooled mixture, egg and about 3 cups flour; beat until smooth.
Mix in enough remaining flour to make a firm dough.
Knead on a lightly floured board until elastic, 5-8 minutes.
Shape into a ball, turn in a greased bowl to grease all over, cover with cloth, and let rise in a warm, draft-free place until doubled in bulk, about 1 hour.
Punch down and knead 1-2 minutes; divide dough in half, shape into 2 loaves, and place in greased 9"x5"x3" loaf pans.
Cover and let rise until nearly doubled in bulk, about 1 hour.
Toward end of rising, preheat oven to 375° F.
Brush loaves with glaze and, if you like, sprinkle with seeds.
Bake 30-40 minutes until well browned and hollow sounding when tapped.
Turn out and cool upright on wire rack before cutting.